Dendrimer-conjugated isotretinoin for controlled transdermal drug delivery

BACKGROUND

In the present study, we aimed to develop a novel isotretinoin delivery model for treating skin diseases, revealing its potential advantages in drug delivery and targeted therapy. Using a self-assembly strategy, we grafted a dendrimer, based on a well-defined branched structure for nanomedical devices, with a well-defined nanoarchitecture, yielding spherical, highly homogeneous molecules with multiple surface functionalities. Accordingly, a self-assembled dendrimer-conjugated system was developed to achieve the transdermal delivery of isotretinoin (13cRA-D).

RESULTS

Herein, 13cRA-D showed remarkable controlled release, characterized by slow release in normal tissues but accelerated release in tissues with low pH, such as sites of inflammation. These release characteristics could abrogate the nonteratogenic side effects of isotretinoin and allow efficient skin permeation. Moreover, 13cRA-D exhibited high therapeutic efficacy in acne models. Based on in vitro and in vivo experimental results, 13cRA-D afforded better skin penetration than isotretinoin and allowed lesion targeting. Additionally, 13cRA-D induced minimal skin irritation.

CONCLUSION

Our findings suggest that 13cRA-D is a safe and effective isotretinoin formulation for treating patients with skin disorders.

Amphiphile desymmetrisation-induced steric relief governs self-assembly pathways in aqueous media

Herein, we show that a straightforward desymmetrisation of a bolaamphiphilic chromophore can tune aromatic interactions and exciton coupling upon self-assembly. As a result, multiple assembled states become accesible offering a facile approach to induce pathway complexity in aqueous media.

Bioinspired crowding directs supramolecular polymerisation

Crowding effects are crucial to maintaining functionality in biological systems, but little is known about their role in analogous artificial counterparts. Within the growing field of supramolecular polymer science, crowding effects have hitherto remained underappreciated. Herein, we show that crowding effects exhibit strong and distinct control over the kinetics, accessible pathways and final outcomes of supramolecular polymerisation processes. In the presence of a pre-formed supramolecular polymer as crowding agent, a model supramolecular polymer dramatically changes its self-assembly behaviour and undergoes a morphological transformation from bundled fibres into flower-like hierarchical assemblies, despite no co-assembly taking place. Notably, this new pathway can only be accessed in crowded environments and when the crowding agent exhibits a one-dimensional morphology. These results allow accessing diverse morphologies and properties in supramolecular polymers and pave the way towards a better understanding of high-precision self-assembly in nature.

Shape-assisted self-assembly

Self-assembly and molecular recognition are critical processes both in life and material sciences. They usually depend on strong, directional non-covalent interactions to gain specificity and to make long-range organization possible. Most supramolecular constructs are also at least partially governed by topography, whose role is hard to disentangle. This makes it nearly impossible to discern the potential of shape and motion in the creation of complexity. Here, we demonstrate that long-range order in supramolecular constructs can be assisted by the topography of the individual units even in the absence of highly directional interactions. Molecular units of remarkable simplicity self-assemble in solution to give single-molecule thin two-dimensional supramolecular polymers of defined boundaries. This dramatic example spotlights the critical function that topography can have in molecular assembly and paves the path to rationally designed systems of increasing sophistication.

Self-assembly and molecular recognition usually depend on strong, directional non-covalent interactions but also topography can play a role in the formation of supramolecular constructs which makes it nearly impossible to discern the potential of shape and motion in the creation of complexity. Here, the authors demonstrate that long-range order in supramolecular constructs can be assisted by the topography of the individual units even in the absence of highly directional interactions.